Question

我试图将.pdf发送到我的应用，让它将每个页面修改为.png，编辑照片，然后将它们修改为一个.pdf。我可以将.pdf转换为多个.png但尝试将它们转换回一个.pdf给我带来的问题是它将每个页面/图像导出到它自己的pdf而不是一个。这只是快速而肮脏的代码，我试图发送.pdf，转换为.pngs，然后回到.pdf而不编辑.pngs。我查看了http://code.tutsplus.com/tutorials/generating-pdf-documents--mobile-11265和Creating a single page pdf file with array of images in iOS?，但图片不在数组中......任何帮助都会非常感激。

- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation{
      NSLog(@"Open URL:\t%@\n"
      "From source:\t%@\n"
      "With annotation:%@",
      url, sourceApplication, annotation);

CGPDFDocumentRef SourcePDFDocument = CGPDFDocumentCreateWithURL((__bridge CFURLRef)url);

size_t numberOfPages = CGPDFDocumentGetNumberOfPages(SourcePDFDocument);

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *filePathAndDirectory = [documentsDirectory stringByAppendingPathComponent:@"temp"];

NSError *error;

if (![[NSFileManager defaultManager] createDirectoryAtPath:filePathAndDirectory
                               withIntermediateDirectories:NO
                                                attributes:nil
                                                     error:&error])
{
    NSLog(@"Create directory error: %@", error);
    [[NSFileManager defaultManager] removeItemAtPath:filePathAndDirectory error:&error];

    NSLog(@"other error: %@", error);
    [[NSFileManager defaultManager] createDirectoryAtPath:filePathAndDirectory
withIntermediateDirectories:NO
attributes:nil
error:&error];   
}

NSMutableData *pdfFile = [[NSMutableData alloc] init];
CGDataConsumerRef pdfConsumer = CGDataConsumerCreateWithCFData((CFMutableDataRef)pdfFile);

for(int currentPage = 1; currentPage <= numberOfPages; currentPage ++ )
{
    CGPDFPageRef SourcePDFPage = CGPDFDocumentGetPage(SourcePDFDocument, currentPage);
    // CoreGraphics: MUST retain the Page-Refernce manually

    CGPDFPageRetain(SourcePDFPage);

    NSString *relativeOutputFilePath = [NSString stringWithFormat:@"%@/%@%d.png", @"temp", @"photo", currentPage];

    NSString *ImageFileName = [documentsDirectory stringByAppendingPathComponent:relativeOutputFilePath];

    CGRect sourceRect = CGPDFPageGetBoxRect(SourcePDFPage, kCGPDFCropBox);

    UIGraphicsBeginPDFContextToFile(ImageFileName, sourceRect, nil);

    UIGraphicsBeginImageContextWithOptions(sourceRect.size, NO, 3);

    CGContextRef currentContext = UIGraphicsGetCurrentContext();

    CGContextTranslateCTM(currentContext, 0.0, sourceRect.size.height); 

    CGContextScaleCTM(currentContext, 1.0, -1.0);

    CGContextDrawPDFPage (currentContext, SourcePDFPage); // draws the page in the graphics context

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    NSString *imagePath = [documentsDirectory stringByAppendingPathComponent: relativeOutputFilePath];

    CGDataConsumerRef pdfConsumer = CGDataConsumerCreateWithCFData((CFMutableDataRef)pdfFile);
    // The page size matches the image, no white borders.

    CGRect mediaBox = CGRectMake(0, 0, sourceRect.size.width, sourceRect.size.height);
    CGContextRef pdfContext = CGPDFContextCreate(pdfConsumer, &mediaBox, NULL);
    CGContextBeginPage(pdfContext, &mediaBox);

    CGContextDrawImage(pdfContext, mediaBox, [image CGImage]);

    CGContextEndPage(pdfContext);

    CGContextRelease(pdfContext);

    CGDataConsumerRelease(pdfConsumer);

    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"dd/MM/yyyy"];

    NSString *end = @".pdf";
    NSString *start = @"Documents/image";
    NSString * timestamp = [NSString stringWithFormat:@"%f",[[NSDate date] timeIntervalSince1970]];
    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent: [NSString stringWithFormat:@"%@%@%@", start, timestamp, end]];

    [pdfFile writeToFile:path atomically:YES];

    NSLog([NSString stringWithFormat:@"%@%@%@", start, timestamp, end]);

}

return YES;
}

Answer 1

您的问题是UIGraphicsBeginPDFContextToFile和CGContextRelease（pdfContext）语句应该在for循环之外。

Answer 2

试试这个（假设您已将所有图像作为UIImageView放在UIScrollView上）：

  /* CREATE PDF */
  self.pdfData = [NSMutableData data];
  NSInteger pageHeight = 800;
  UIGraphicsBeginPDFContextToData(self.pdfData, CGRectMake(0,0,768,pageHeight), nil);//768*792/612
  CGContextRef pdfContext = UIGraphicsGetCurrentContext();
  for (int page=0; pageHeight *page < scrollView.frame.size.height; page++)
  {
      UIGraphicsBeginPDFPage();
      CGContextTranslateCTM(pdfContext, 0, -pageHeight * page);
      [scrollView.layer renderInContext:pdfContext];
  }

  UIGraphicsEndPDFContext();

  /* EXPORT PDF */
  NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
  NSString* documentDirectory = [documentDirectories objectAtIndex:0];
  NSString* fileName = [self genRandStringLength:7];
  fileName = [NSString stringWithFormat:@"%@.pdf", fileName];
  NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:fileName];

  // instructs the mutable data object to write its context to a file on disk
  [self.pdfData writeToFile:documentDirectoryFilename atomically:YES];

将多个.png组合成一个.pdf

2 个答案: